peeling

The insulated wall panels have a layer of plastic on the exterior side that protects the finish. Peeling it off is somewhat addictive, and makes for a fun, Saturday afternoon family activity.

milling

We've been playing with the CNC (computer numerical control) milling machine at FIU's School of Architecture. This is a new technology for us (though it's pretty standard for architecture students nowadays) and we're trying to figure out how to use it. In the next two weeks, we'll use the CNC to cut metal sheets into custom trim to use around the beams and purlins that pop through the exterior walls of the house. Today, we carved a large piece of MDF (medium density fiberboard) into a large construction site sign. This little project was a dry run for another project (an exhibition that opens in a couple of weeks) and gave us an opportunity to play with the technology. Eric Peterson, scholar, craftsman and fellow faculty member at FIU, was instrumental at making this work.

Admittedly, the video of the CNC machine at work is not exactly gripping. The system includes software that translates three-dimensional data into carving patterns, and instructs the milling machine on how to subtract areas from solid materials. The video is backwards (reversed left to right) because the only camera I had available was the built-in video on my laptop.

more wall panels

Our installer is making progress on the wall panels. They've put up about half the panels, but still have some tricky areas and a lot of trim to do in the coming weeks. For now, we're enjoying having a chance to see the front of the house (left, with the porch in the foreground) and the courtyard (after the break) take shape.

more wall panels

The insulated steel wall panels are going up at the garage and the front porch, and by the end of next week we should have most of the wall panels in place. We'll write about the installation process (and sing the praises of our installers) later. Right now, we wanted to share some photographs of the panels in different light conditions, to show how the color and texture change with the weather and time of day...

wall panels, continued

The erection crew put up the first two wall panels this afternoon, in between solving one problem (the screws provided were too short) and running into another (the third panel would line up in a spot with no supporting girts or other structure). Nonetheless, the installed panels give us a good idea of how the exterior is going to come together. The silver finish (seen here with Holly peeling back the protective plastic wrap) is really beautiful. Because it reflects so much of the ambient light around it, the silver finish appears to change color as the viewer moves. It also changes as the light fluctuates between direct sunlight and the indirect light of an overcast sky.

wall panels

For the last few days, our steel erectors have been preparing to install the insulated steel wall panels. At 3" thick, these panels are thinner than the roof panels, but still have an insulating value of at least R-24. Like the roof panels, they are held in place with clips designed to avoid breaking the thermal barrier, and they use two kinds of sealant (gooey stuff from a tube and self-adhesive strips) to maintain a continuous moisture barrier.

Preparing the panels and the frame is taking some time and care...

roof panels complete

Late this afternoon, the steel erector installed the last of the insulated roof panels. There's still a lot of work to do on the roofs, including trim, gutters and photovoltaic panels, but it's really nice to see all the panels in place.

Design Miami

"How much does your house weigh?"

Buckminster Fuller's famous aphorism-in-the-form-of-a-question brilliantly raised concerns that had escaped the focus of architects, but would become central to the practice of many of the twentieth-century's key figures. Fuller's interest in efficiency and his close study of natural forms led to the invention of the geodesic dome, the dymaxion living units and the concept of synergy. Design Miami worked with Fuller's friend, Norman Foster, to bring two projects - a restored fly's eye dome and a new dymaxion car built by the British architect - to the Design District this week. It was spectacular to spend time poring over both, as well as the accompanying exhibition of photographs and drawings. And that's not all Design Miami had for us this year...

roof panels

Our steel erector began putting the insulated roof panels up this week. Together with the insulated wall panels and the metal trim, this comprises the final layer in the prefabricated shell of the house. The panels themselves are pretty impressive:

action photos

Steel construction makes for some pretty cool photos.

Here, one of the erection crew is trimming some of the roof decking. Of the scores of panels of B-decking used in the house, only two needed to be trimmed. This efficiency - less material used, less waste on site, lower transportation costs - is one of the advantages to prefabrication.

One disadvantage is the need for specialized (read: expensive) machinery, like boom cranes...

the week ahead

Looking forward at the week ahead, we're anticipating a lot of work at tin box. Our erector should be able to finish installing the roof decking this week (we're still waiting on two pieces of steel that weren't shipped with the z-purlins). The exterior roof panels arrive Tuesday, and should start going up right away. Our panel manufacturer plans to begin fabricating the exterior wall panels Monday and deliver them to the site Friday.

Meanwhile, the neighbors clearly approve of the project...

decking

Our erector started installing the roof decking yesterday. These gorgeous corrugated sheets are High Shear B Deck (HSB-36), a structural roof decking that comes in 36" wide and 1.5" deep sheets. The decking is fastened to the z-purlins with TEK screws (which don't need a pre-drilled hole), and will act as a structural diaphragm under the insulated roof panels, which are also structural. Together, the decking and roof panels will deal with the combination of tensile, compressive and shear forces generated by hurricane force winds. They will also support the weight of the vegetated roof that we plan to add someday.

The B Deck will also make for a great ceiling, in combination with the z-purlins...

roof

From the Kingspan factory in Deland, FL, comes this progress photo of our roof panels. Our roof uses KingZip insulated metal panels with a standing-seam joint. We chose 4" thick panels, which will give us an insulating value of R-32 (exceptional by Florida standards). We could have gone up to 6" thick, which yields R-48, but this would be a bit excessive in South Florida.

Each 42" wide panel will hold two solar panels, which adhere directly to the steel surface of the roof panels. The panels have a galvalume finish whose high albedo value (a measure of reflectivity) means they will reflect most of the sunlight that hits them, minimizing the direct heat gain.

The roof panels are cut to length in the factory, which helps eliminate on-site waste and reduce energy wasted in transit (one benefit to prefabrication). The pieces can come in lengths up to 52', the length of a flatbed truck. Our longest pieces are about 32'. We'll write more about the roof when it starts arriving, early next week.

purlins, continued

Our erector started installing the purlins this week. The purlins are z-shaped steel sections that span between the beams and support the weight of the roof panels. Our purlins are a little unusual in that they pass over the beams, rather than sitting in the same plane as the beams. This, along with the use of corrugated steel decking between the purlins and roof panels, is necessary for the roof to resist hurricane-strength winds. (The corrugated decking is hiding under the blue tarp at right).

purlins

We'll write more about the purlins over the weekend, but for now, we're excited to have the next pieces of steel going up. By the end of next week, we hope to have all the secondary structure of the roofs in place and ready for the roof panels to go up.

what you don’t see

Notice the conspicuous absence of a dumpster.

One big advantage to prefabrication is that it significantly reduces construction waste. The primary structure is nearly complete, and so far the crew has only had to dispose of a few tiny pieces of scrap steel. The foundation and slab were poured with a minimum of waste (most of the wood forms were taken away to be reused) and the utilities were roughed in with only a couple of cardboard boxes worth of scrap pipe needing to be carted away.